notifyOn Filtering over WebSocket

The notifyOn option on the accountSubscribe and programSubscribe WebSocket methods lets a subscription skip updates for accounts that a transaction write-locked but never wrote to. The same filter is available over gRPC — see notifyOn Filtering for the gRPC version.

The problem: write locks generate duplicate updates

On Solana, the validator emits an account update for every account a transaction write-locks — even when no instruction actually wrote to the account, so its lamports and data are unchanged. For busy accounts, that means a steady stream of duplicate “nothing changed” notifications that consume bandwidth without carrying new information.

Filter modes

notifyOn takes one of two string values:

Value	Sends a notification when	Use it for
`"lock"`	A transaction write-locks the account, whether or not it writes to it	The default — full visibility, including accounts merely touched by a transaction
`"write"`	A transaction actually writes to the account	Cutting no-op noise — most consumers lose nothing

Two details worth knowing:

A write of identical data still counts as a write and is delivered. write filters out lock-only touches, not writes that happen to leave the same bytes. In practice these identical-data writes are rare — under 5% of updates in most cases.
The updates write drops are exact duplicates of state you already received. If you rely on notifications as a “this account was locked by a transaction” signal (e.g., activity tracking), stay on lock.

Subscriptions that omit the field behave exactly as before, so it’s safe to add to an existing subscription.

Use it in `accountSubscribe`

Add notifyOn to the config object:

const ws = new WebSocket('wss://mainnet.helius-rpc.com/?api-key=<API_KEY>');

ws.on('open', () => {
  ws.send(JSON.stringify({
    jsonrpc: '2.0',
    id: 1,
    method: 'accountSubscribe',
    params: [
      '<ACCOUNT_PUBKEY>',
      {
        encoding: 'jsonParsed',
        commitment: 'confirmed',
        notifyOn: 'write' // skip no-op updates
      }
    ]
  }));
  setInterval(() => ws.ping(), 30_000);
});

ws.on('message', (data) => {
  const msg = JSON.parse(data.toString());
  if (msg.params?.result) console.log(msg.params.result);
});

Use it in `programSubscribe`

The same key works in the programSubscribe config object, filtering no-op updates across every account the program owns:

ws.send(JSON.stringify({
  jsonrpc: '2.0',
  id: 1,
  method: 'programSubscribe',
  params: [
    '<PROGRAM_ID>',
    {
      encoding: 'jsonParsed',
      commitment: 'confirmed',
      filters: [{ dataSize: 165 }],
      notifyOn: 'write' // skip no-op updates
    }
  ]
}));

Parsing is fail-open: only "write" (case-insensitive) opts in. Anything else — absent, a typo, an unknown token — resolves to lock, so a mistake keeps you on the all-updates path instead of erroring or silently dropping data.

accountSubscribe

Full accountSubscribe method reference, including notifyOn.

programSubscribe

Full programSubscribe method reference, including notifyOn.

notifyOn Filtering (gRPC)

The same filter on LaserStream gRPC accounts filters.

How to Use accountSubscribe

Guide to streaming account updates over WebSocket.

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notifyOn Filtering over WebSocket

The problem: write locks generate duplicate updates

Filter modes

Use it in `accountSubscribe`

Use it in `programSubscribe`

accountSubscribe

programSubscribe

notifyOn Filtering (gRPC)

How to Use accountSubscribe

​The problem: write locks generate duplicate updates

​Filter modes

​Use it in accountSubscribe

​Use it in programSubscribe

​Related

accountSubscribe

programSubscribe

notifyOn Filtering (gRPC)

How to Use accountSubscribe

The problem: write locks generate duplicate updates

Filter modes

Use it in `accountSubscribe`

Use it in `programSubscribe`

Related